node/test/parallel/test-net-connect-immediate-finish.js

'use strict';
const common = require('../common');
const assert = require('assert');
const net = require('net');

const client = net.connect({host: '...', port: common.PORT});

client.once('error', common.mustCall(function(err) {
  assert(err);
  assert.strictEqual(err.code, err.errno);
  assert.strictEqual(err.code, 'ENOTFOUND');
  assert.strictEqual(err.host, err.hostname);
  assert.strictEqual(err.host, '...');
  assert.strictEqual(err.syscall, 'getaddrinfo');
}));

client.end();